638399907096 has 128 divisors (see below), whose sum is σ = 1848365568000. Its totient is φ = 179972001792.

The previous prime is 638399907049. The next prime is 638399907097. The reversal of 638399907096 is 690709993836.

It is a self number, because there is not a number n which added to its sum of digits gives 638399907096.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638399907097) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7117440 + ... + 7206576.

It is an arithmetic number, because the mean of its divisors is an integer number (14440356000).

Almost surely, 2^638399907096 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638399907096, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (924182784000).

638399907096 is an abundant number, since it is smaller than the sum of its proper divisors (1209965660904).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638399907096 is a wasteful number, since it uses less digits than its factorization.

638399907096 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89721 (or 89717 counting only the distinct ones).

The product of its (nonzero) digits is 119042784, while the sum is 69.

The spelling of 638399907096 in words is "six hundred thirty-eight billion, three hundred ninety-nine million, nine hundred seven thousand, ninety-six".